Telephone-transmitter.



J. BEDDING. TELEPHONE TRANSMITTER. APPLICATION FILED JUNE 17, 1910.

1,0953%, 7 Patented m 5,1914.

2 SHEETS-SHEET l.

K Q55 'kk ci 50 J; BEDDING.

TELEPHONE TRANSMITTER. APPLIOATIMI FILED JUNE 17, 1910.

1,995.354, I Patented May 5, 1914.

2 SHBETSSHEET 2.

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UNITED s'ransran ion JEROME BEDDING, F MALDEN, MASSACHUSETTS, ASSZIIGNORTO FRANCIS H. LORD,'

TRUSTEE, OF SOUTH WEYMOUTH, MASSACHUSETTS.

TELEPHONE-TRANSMITTER.

Specification of Letters Patent. I

Patented May To all tr/m. it may concern I Be it known that I, Jnnonr.BEDDING, a citizen of the United States, residing at Malden, county ofMiddleses, and State of Massachusetts, have inventedan Improvement inTelephon'e-Transmitters, of which the following description,inconnectionwith the accompanying drawing, is a. specificationrlike characters onthe drawing repre- Q senting like parts.

This invention relates to telephone transmitters and has for. its objectto provide av novel transmitter which is constructed so that it can'be,successfully used with currents of a comparatively high voltage.

The telephone transmitter now in universal use is designed to be usedwith a low voltage current and is so constructed that it the voltageincreases beyond a certain amount snapping: or hissing noises areproduced which interfere materially with the transmission" of sound.-voltage can only be used on a comparatively short line because if thelength of the line is increased beyond certain limits the resistance ofthe line will be such as to' preclude the use of a low voltage.Accordingly for long distance lines it has become the practice to use aninduction coil or transformer in connection with the telephone for thepurpose of converting the low voltage local cur-- rent connected to thetransmitter into a current of higher voltage which is used on the line.The use of an induction coil in this connection. has some disadvantageshow ever. partly due to the hysteresis developed in the induction coiland partl due to the tact that the current induced by the induction coilis an alternating current which is not as desirable in many ways fortransmitting sound as a direct current My invention aims to provide anovel tran mitter which can be used with a direct 'urrent of highvoltage so that the transmitter may be connected directly to a longdistance line without the use of an induction coil or transtorn'ier andwill not be affected in any disadvantageous way by the employment of adirect current of sutiiciently high voltage to' carry the full length ofthe long distance line.

In the drawings wherein I have illustrated one embodimentof myinvention, Figure l is a side view of a telephone transmitter embodyingthe invention; Fig. 2 its a sec A current of low' tion on the line tcaFig. 1; Fig. 3 shows the back side of the transmitter 'with the coverremoved; Fig. tis a section transversely through a portion oi thetelephone transmitter on the line w o, Fig. 2; Fig. is a detailSCtl()llltll-\'l\\ of one of the cells or variable resistance elements.

My improvedtelephone transmitter coniprises a plu 'ality of separatecells or variable resistance units which are connected in series witheach other and with the line and all of which are so situated relativeto the main sound-transmitting diaphragm of the instrument that whensaid diaphragm'vibra (es. the resistance of all the resistance unitswill be varied simultaneously. here the resistance units are connectedin series the total resistance in the line is the sum total of theresistance of the individual units which are connected in series. and asthe resistance of all the units varies simultaneously a much greatertotal variation in the resistance of the line is secured than ispossible with a single cell or r sistance unit. In this way it ispossible to use a current of a high voltage without any deleteriouseffects. The individual cells or resistance units are confined within asuitable casing 23 which supportsthe main sound-transmitting diaphragml. the front 5 of the casing having the usual opening for .thetransmission of the sound vibrations. and preferably carrying a mouthpiece (3, as usual. The main diaphragm 4 may be secured in the casing inany suitable way without departing from the invention. have herein shownthe edge t-liere'otas clamped between the edge of the front 5 and themain bodyof the casing. The trout 33 of the casing is shown as removableand is secured in place by the clamping bolts 9.

'and l have shown the edge of the main dia phragm r as confined betweentwo gaskets 10 of rubber or other similar insulating material which areclamped in place by said clamping bolts.

'lheseparate resistance units are support-- -cd by a plate ll ofinsulating material which rent passes. One of these cells is shown in.

enlarged section in Fig. 5 and it comprises extends through the end ofthe cell and from which extends a stem 16 of good conducting material bywhich the cell is sup ported in the plate 11. The cavity in the body 12is filled with granulated carbon or similar material 17, and preferablysome high resistance carbon will be used, such, for instance, as wouldbe obtained by finely pulverizing the carbon. 5 Said cavity is closed bya flexible diaphragm 18 of con ducting material which is clamped to thebody by a clamping ring 19, said ring preferably being hexagonal orflat-sided so as to permit it to be readily turned. I prefer to make theflexible diaphragms 18 of pure silver as I have found that when made inthis way the diaphragms are more sensitive and will not become oxidizedby the current. The flexible diaphragm 1.8 of each. cell is arranged tobe vibrated by the vibratious of the sound-receiving diaphragm 4, sothat the resistance of the cells will vary in accordance with the soundvibrations to be transmitted. There are various ways inwhich this can beaccomplished, but I find good res lts can be secured by mechanicallyconnecting each diaphragm 18 to the main diaphragm 4:.

As herein shown each cell diaphragm has extending therefrom a. screw 29on which is screw-threaded two clamping nuts 2.0 and 21 between whichthe diaphragm .4 is

clamped, thus making a rigid connection;

between said diaphragm 4t and each cell diaphragm. An other suitablearrangement by which the vibrations of the diaphragm 4 will betransmitted to the cell diaphragms may be adapted, however. withoutdeparting from the invention.

A suiiicient number of the resistance units 1,095,3lld

The electrical connection between the various resistance units may bemade in any suitable way, and as herein shown the clamping ring 19 ofeach cell is electricallyv connected with the stem 16 of thenext cell bymeans of a wire 22, as shown in Fig. 3.

- These wires 22 may be secured to the clamp ing nuts 19 and stems 16 inany suitable way. i have herein shown each wire as soldered or otherwisepermanently connected-to one clamping nut 19 and as passing through anaperture 23 in the plate 11 and as secured to the stem 16 of the nextcell by means of two clamping nuts 24 thereon. The various resistancecells are insulated from each other and thismay conveniently be done byinclosing each clamping nut 19 man envelop 25 of insulating material.The wires 26 and 27 of the line are shown as leading to and connectedwith tWo terminals or binding posts 48, 49, and the binding post 49 isconnected by of the first cell of the series, while t e binding post isis connected by a wire 31 with the stem 16 of the last cell of theseries. With such a construction it will be seen that whenever the maindiaphragm alvibrates the vibrations will be transmitted to all the celldiaphragms 18, and thus the resistance in all the cells will. varysimultaneously. Since 9 the resistance between the terminals 48 and 49is the sum total of the resist time of all the cells connected inseries, it will'be apparent that the amount of variation in theresistance of the line due to the vibration of the diaphragm 4 will bethe sum total of the variation in the resistance of all such cells. Withsuch an arrangement it is possible to use a current ofa comparativelyhigh volt age without interfering in any way with the proper use of theinstrument. This onables me to/connect the instrument directly to longdistance telephone line without the use of induction coils and yet touse a cur- 1 rent of suiliciently high voltage to overcome i theresistance of the line Without any such and the voltage of the currentto be used.

' llnder ordinary circumstances I would propose to connect all the-cells in series, as shown in the drawings, but under some circumstances it may be desirable to divide the cells into two or moregroups and connect the cells of each group in series while the groupsare connected in multiple arc. The cells are each insulated from thecasing and this may be done in various ways. If the diaphragm 4 is ofmica or other insulating, l

' material, said diaphragm will act as an in sulator, but if saiddiaphragm is of metal or any other conducting material then I may makethe nuts 20 and 21 of insulating material.

l nal strains therein.

loss in current strength will interfere with the proper use of theinstrument.

To order to get the best results it is desirable that the diaphragm 4should not be subjected to any internal strains due to its connectionwith the individual cells. it:

will readily be seen that if all the cells l2 were rigidly sustained bythe plate ll. and any one or more cells should be out of properaliuement, the diaphragm 4 would be subjected to internal strains whichwould interfere with the transmission of delicate sounds. In order toprevent this i have provided a novel Way of supporting the in dividualcells so that each will be yicldingly sustained and can assume such aposition relative to the main diaphragm as to prevent the presence ofany objectionable inter hile there are varia wire 30 with a clampin nut19 ous ways of yieldingly supporting the indi; vidual cells to securethis object, I have shown a construction wherein the stem of each cellpasses loosely through a sleeve or bushing sustained by the plate 11 andis centered and properly positioned by two springs 36, 37 that encirclethe stem and are situated at either end of the bushing, one

spring 37 being confined between said bushing and the cell, and theother spring being confined between said bushing and the nuts 24. By'properly adjusting the clamping nuts 24, it is possible to give the twosprings 36, 37 the proper tension so that each cell will be supported insuch a manner that it will not subject the diaphragm 4 to any strainbecause of its position.

The casing 3 may be made in a variety of ways without departing from theinvention. I have herein shown it as comprising the central ring 39 toone side of which the i plate 11 is connected and to the other side ofwhich the front plate 5 isseeured, the

edge of the diaphragm 4 being clamped between the front plate 5 and thebody portion 39. as above stated. The back side of the casing is formedby a removable cap piece 4:0 which covers the projecting ends of thestem 16 and which is secured to the plate 11 in any suitable orappropriate way. These features of construction, however,

inay be varied withoutgleparting from the 1nvent-ion.

I find it is of advantage 'to make the clamping nuts 19 of such a shapethat they fit tightly together, as shown, for in this way a solid wallas it were is presented hack of the diaphragm 4 and the vibrations tendsto prevent the finely-granulated car-.

thereofare more readily transmitted to the cell diaphragms.

l have shown the cell diaphragms as cor rugated and this'is of advantagebecause it hon 17 from caking.

l/Vhile I have illustrated and described the cells as all connected inseries, which is the arrangement that is preferable when a hi h voltagetzurrent is to be used, yet it would he possible to connect the cellspartly in series. and partly in multiple it the circumstances underwhich the instrument is used are such as to require a current of aSmaller voltage.

I have illustrated herein the preferred embodiment only of my inventionand it is obvious that various changes in the constructional details ofthe parts may be made without departing from the invention.

.Having fully described my invention,

what I claim as new and desire to secure by Letters Patent is ..l.-In atelephone transmitter, the combination with a; cell-supporting member,of a plurality of separate cells independently and adj List-ablysupported thereby, each filled with granular material.; flind providedwith means separate fromsaid supporting'mean s cell independently to themain diaphragm, and means electrically connecting said cells in series.-52. In a telephone transmitter, the combination with a plurality ofseparate cells,

vided with a flexible diaphragm, of means to ad ustably support eachcell, a main dia- -ing means for connecting the flexible diaphragm ofeach cell independently to the main diaphragm, and means electricallyconnccting-said cells in series.

3.'In a telephone transmitter, the combination with a casing, of a maindiaphragm secured therein, a plate sustained thereby, a plurality ofseparate cells each filled with granular material and having a flexibledia- .phragm, means connecting each flexible diaphragm to'the main diahragm, each cell and springs acting on each stem on opposite sides ofthe plate.

4. In a telephone transmitter, the. combination with a cell-supportingmember, of a plurality of separate independently adjustfrom each otherand each filled. with high resistance granular material and providedwith a flexible diaphragmga main diaphragm, means to secure the flexiblediaphragm of each cell independently to the main diaphragm, and meanselectrically connecting said cells in series.

In a telephone transmitter, the combiplurality of separate cells eachfilled 'Wli h ble diaphragm and each having a stem extending therefromand passingthrough the plate, a main diaphragm, means to secure theflexible diaphragm of each cell inde-' pendently to the main diaphragm,and

phragm, of a plurality of cells of insulating material each having anopen end, a fle'xible idiaphragm cl singfi 9nd of -ii a flexiblediaphragm, a main de arts,

-for securing the flexible diaphragm of each each filled with granularmaterial and proable cells supported thereby and insulated nation witha. cell-supporting plate, of a' granular material and provided withafiexi I nation with a main sound-receiving dia phragm, means separatefromsaid support: 4

having a stem extending t rough said plate,

means connecting electrically the cells in hexagonal clamping ringsscrew-threaded to each cell and adapted to hold the corren sponclingdiaphragm in place, an envelogidfs F insulating material inclosing eachclamping ring, means to support said cells with the clamping ringsengaging each other, a terminal in each cell, and an electricalconnection between the clamping ring of each cell and the terminal ofthe adjacent cell.

8. In a telephone transmitter, the combination with a casing, of a maindiaphragm therein, a plate sustained by the casing, a plurality ofcells, within the casing each filled with granular material, a flexibledia phrugm forming one side of each cell, a. termemes minal in eachcellgeach terminal having a stem extending therefrom and projectingthrough said plate nn electrical connection between the stem of eachcell and the l'leKible diaphragm of the adjacent cell. and two springson each stem, one on each side of said plate.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

JEROME BEDDING.

Witnesses: I I

LOUIS G. SMITH, THOMAS J. DRUMMQND;

